Synchrony in the New World: an Example of Archaeoethnology
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10.1177/1069397105282507Cross-CulturalPeregrine / SYNCHRONY Research / FebruaryIN THE NEW 2006 WORLD Synchrony in the New World: An Example of Archaeoethnology Peter N. Peregrine Lawrence University Christopher Chase-Dunn and colleagues have demonstrated cycles of synchronous growth and decline in cities in East Asia and in the Mediterranean. They argue that synchrony is rooted in systems of economic and political interdependence, cutting across broad re- gions of the world for long periods of history. Using a new strategy for cross-cultural research in the anthropological sciences— archaeoethnology, the cross-cultural analysis of archaeological cultures in a diachronic mode—the author examines whether set- tlement synchrony has occurred in the New World and if so, whether it implies widespread economic and political interdepen- dencies across long periods of time. Keywords: archaeology; New World prehistory; cultural evolu- tion; time-series analysis Christopher Chase-Dunn and colleagues have recently demon- strated an interesting pattern of urban dynamics in Europe, North Africa, and Asia during the past 4,000 years (e.g., Chase-Dunn & Hall, 1997; Chase-Dunn & Willard, 1993). They show, using the geographical area and estimated population of cities known from historical and archaeological contexts, that changes in city size in Cross-Cultural Research, Vol. 40 No. 1, February 2006 1-12 DOI: 10.1177/1069397105282507 © 2006 Sage Publications 1 2 Cross-Cultural Research / February 2006 one part of this broad region anticipate and perhaps cause change in other parts of the region (Chase-Dunn, Manning, & Hall, 2000). Chase-Dunn and colleagues term this pattern “city synchronicity” and demonstrate long-term patterns of synchrony across large re- gions of the Old World (Chase-Dunn & Manning, 2002). Chase-Dunn and colleagues propose several causal factors underlying city synchrony.They suggest long-distance trade could have produced economic forces strong enough to bring city growth and decline into synchrony, similar to the way the modern world system produces integration between the nations of the world (Chase-Dunn & Hall, 1997; Chase-Dunn & Willard, 1993). They also suggest that the impact of steppe nomads or epidemic diseases on population size and movement could have produced a pattern of synchrony as people centralized for defense or moved to avoid disease-ridden areas or locations on the path of nomad conquest (Chase-Dunn & Manning, 2002). Finally,they suggest that climate change could have produced a pattern of synchronous expansion and contraction of cities (Chase-Dunn, Alvarez, & Pasciuti, 2002; Chase-Dunn & Manning, 2002). This last suggestion, that climate change could have produced a pattern of city synchrony in the Old World, is a particularly inter- esting one, as it matches ideas coming from other areas of social science research (e.g., Kick & Jorgensen, 2003; Lamb, 1995). If cli- mate changes were extensive enough to affect all of Eurasia, we might expect these changes to have affected the New World as well. The purpose of this article is to examine whether there is evi- dence of settlement synchrony in the New World during the past 4,000 years and, if so, whether synchronous change correlates with change in the Old World. Such a finding would support the idea that climate change is a primary cause of city synchrony. METHOD To demonstrate city synchrony in the Old World, Chase-Dunn and colleagues relied on data from a variety of well-established sources, particularly Tertius Chandler’s (1987) remarkable com- pendium of city data. Unfortunately, these sources are inadequate for the New World except for the relatively recent past, and even newer sources (e.g., Modelski, 2003) lack good data for the prehis- toric New World. I chose, instead, to rely on the information pre- sented in Volumes 5, 6, and 7 of the Encyclopedia of Prehistory Peregrine / SYNCHRONY IN THE NEW WORLD 3 (Peregrine & Ember, 2001-2002). From the information in these volumes, I coded a set of “cultural complexity” data, recently pub- lished with a full description of my coding methods (Peregrine, 2003). These data have already been used in several published studies (e.g., Peregrine, 2001; Peregrine, Ember, & Ember 2004) and appear to be both valid and reliable. Thus, they appear to be a good set of data for this study. Chase-Dunn and colleagues use estimates of individual city size and population in their analyses. This was not possible for the New World as only a handful of prehistoric cities have been investigated closely enough to provide such data, and the literature on others can only provide gross estimates. Similarly,there are large areas of the New World where archaeological and historical research is only beginning to build a firm knowledge base (for example, West Mexico and southern Central America). The data set I employ here uses “archaeological traditions” rather than individual cities as the basic units of analysis. Archaeological traditions are amal- gams of archaeologically described societies that are similar in their political and economic forms, are bounded in time and space, and were created to provide roughly comparable units for doing cross-cultural archaeology,or archaeoethnology (Peregrine,2001). Because my units of analysis are different from those employed by Chase-Dunn and colleagues, I had to employ a somewhat differ- ent method of analysis as well. I chose to use the percentage of cases with settlements larger than 400 people as my dependent variable. This may not seem urban, but anthropologists have dem- onstrated that settlements with more than 400 people require for- mal mechanisms to maintain peace and stability (e.g., Chagnon, 1975). Because most New World societies did not have state forms of government, I suggest that using settlements of greater than 400 people illustrates variation in New World population central- ization better than relying on the criteria used by Chase-Dunn and colleagues (they define cities as having more than 10,000 residents). I coded cases in a time series with 100-year intervals for the period from 2,500 to 500 years ago. I also divided the New World into three broad regions for comparison: North America, Meso- america (including Central America), and South America. To test whether my coding method produced results similar to Chase- Dunn and colleagues, I coded a set of Old World archaeological tra- ditions using settlements with more than 400 residents indicative as incipient urbanization. Figure 1 offers a plot of the results 4 Cross-Cultural Research / February 2006 (showing percentage of archaeological traditions with such settle- ments). Comparing Figure 1 with the same time period in Figure 5 demonstrates that the two methods produce reasonably similar results with one caveat, that the percentage method works poorly for highly urbanized areas, such as West Asia, during this period, as there tend to be few if any cases that lack cities. RESULTS Figure 2 plots the percentage of cases with settlements with more than 400 residents across time for North America, Mesoamerica, and South America. There does appear to be evi- dence for a pattern of settlement synchrony. Specifically, Mesoamerica and South America appear to show a synchronous pattern of growth and decline from about 2,100 to 1,100 years ago, with South America lagging behind Mesoamerica by roughly 200 years. After about 1,500 years ago, Mesoamerica and North Amer- ica begin a pattern of synchronous counterchange, with the per- centage of settlements with more than 400 people declining as the percentage in North America grows. Further evidence for New World synchrony is shown in Figures 3 and 4. Figure 3 is a time-series plot showing the cross-correlation of the percentage of cases with settlements of more than 400 inhab- itants between Mesoamerica and South America and demon- strates a statistically significant correlation with a lag of 200 years. Thus, the percentage of cases with settlements of more than 400 people in South America increases in a way similar to that in Mesoamerica but about 200 years later. Figure 4 shows a similar plot for the period between 1,500 and 500 years ago for Mesoamerica and North America and demonstrates a statistically significant negative correlation with a time lag of roughly 100 years. Here the percentage of cases with settlements of more than 400 people in North America increases as those in Mesoamerica decline. DISCUSSION What might explain these patterns of synchrony? As noted ear- lier, Chase-Dunn and colleagues propose four explanations for the Old World: long-distance trade, invasions of steppe nomads, Peregrine / SYNCHRONY IN THE NEW WORLD 5 100₉00 Europe East Asia South Asia Middle East 80₉00 60₉00 40₉00 20₉00 Percent of Cases with Settlements over 400 of Cases with Settlements over Percent 0₉00 3000 2900 2800 2700 2600 2500 Years Ago Figure 1: Percentage of Archaeological Traditions in the Old World With Settlements With More Than 400 Residents for the Period Between 3,000 and 2,500 Years Ago epidemic diseases, and climate change. Of these, both invasions of steppe nomads and epidemic diseases are unlikely causes of New World synchrony.Although warfare and conquest certainly played a role in population centralization in the New World and some- times did involve nomadic groups such as the Chichimecs, these all occurred (as far as we know) on a limited scale, regional at the larg- est (LeBlanc, 1999). No evidence of large-scale conquest covering more than a fairly limited geographic